The evolution of the tanmātras has been variously described in the Purāṇas and the Smṛti literature. These divergent views can briefly be brought under two headings: those which derive the tanmātras from the bhûtas and those which derive them from the ahaṃkāra and the bhûtas from them. Some of these schools have been spoken of in the Barabara Muni’s commentary on the _Tattvatraya_—a treatise on the Rāmānuja Philosophy—and have been already explained in a systematic way by Dr. B. N. Seal. I therefore refrain from repeating them needlessly. About the derivation of the tanmātras all the other Sāṃkhya treatises, the _Kārikā_, the _Kaumudī_, the _Tattvavaiśāradī_, the _Sūtra_ and _Pravacana-bhāshya_, the _Siddhāntacandrikā_, _Sūtrārthabodhinī_, the _Rajamārtaṇḍa_ and the _Maṇiprabhā_ seem to be silent. Further speaking of the tanmātras, Vijñāna Bhikshu says that the tanmātras exist only in unspecialised forms; they therefore can be neither felt nor perceived in any way by the senses of ordinary men. This is that indeterminate state of matter in which they can never be distinguished one from the other, and they cannot be perceived to be possessed of different qualities or specialised in any way. It is for this that they are called tanmātras, i.e. their only specialization is a mere thatness. The Yogins alone perceive them. Now turning towards the further evolution of the grosser elements from the tanmātras, we see that there are great divergences of view here also, some of which are shown below. Thus Vācaspati says: “The earth atom is produced from the five tanmātras with a predominance of the smell tanmātra, the water atom from the four tanmātras excepting the smell tanmātra with a preponderance of the taste tanmātra, and so on” (I. 44). Thus here we find that the ākāśa atom (aṇu) has been generated simply by the ākāśa tanmātra; the vāyu atom has been generated by two tanmātras, śabda and sparśa, of which the sparśa appears there as the chief. The tejas atom has been developed from the śabda, sparśa and rûpa tanmātras, though the rûpa is predominant in the group. The ap atom has been developed from the four tanmātras, śabda, sparśa, rûpa and rasa, though rasa is predominant in the group, and the earth or kshiti atom has been developed from the five tanmātras, though the gandha tanmātra is predominant in the group. Now the _Yoga-vārttika_ agrees with Vācaspati in all these details, but differs from him only in maintaining that the ākāśa atom has been generated from the śabda tanmātra with an accretion from bhūtādi, whereas Vācaspati says that the ākāśa atom is generated simply by the ākāśa tanmātra.[30]